A RAW file contains the original image information as it comes off the sensor. No in-camera processing is applied. This will be done afterwards on your PC with special software.
TIFF file only retains 8 bits per channel of information but it will take up twice the storage space because it has three 8 bit color channels compared to one 12 bit RAW channel. JPEG resolve this issue by compression, at the cost of image quality. So RAW offers the best of both as it preserves the original color bit depth and image quality and saves storage space compared to TIFF. Some cameras offer nearly lossless compressed RAW.
Many of the camera settings which were applied to the raw data can be undone when using the RAW processing software. For example, white balance, sharpening, levels and color adjustments can be undone and recalculated based on the raw data. Also, because RAW has 12 bits of available data, you are able to extract shadow and highlight detail which would have been lost in the 8 bits per channel JPEG or TIFF format.
The only disadvantage of RAW files their formats differ between camera manufacturers, and even between cameras, so dedicated software provided by the manufacturer has to be used. Furthermore, opening and processing RAW files is much slower than JPEG or TIFF files. To resolve this issue, some cameras are offering the option to shoot in RAW and JPEG at the same time. As cameras become faster and memory cards cheaper, this option has no longer performance or storage issues. It allows you to organize and edit your images in a faster way with regular software using the JPEGs. But you retain the option to process in RAW those critical images or images with problems. Third party image editing and viewing software packages are becoming RAW compatible with most popular camera brands and models. An example is Adobe Photoshop CS. However, the way Photoshop processes RAW files can be different from the way the camera manufacturer’s software does it and not all settings may be recognized.